Tool joint



May 29, 192s. 1,671,579

E. E. GREVE TOOL JOINT Filed Noma?. 1920 gwdg ' Patented May 29,v 192.8.

UNITED STATES EDGAR E. GREVE, F BELLEVUE, PENNSYLVANIA.

TOOL

Application led November My invention relates to improvements in tooljoints particularly adapted for use in connection with rotary drillingtools for earth boring, although it is, of course, ap.- plicable forother purposes.

In a rotary well drilling tool, the drill bit is carried at the end of ahollow shaft comprising sections of pipe jointed together. As the depthof the bore increases, new sections of pipe are inserted. In order t0change the bit after it has become worn, or to withdraw the bit for anypurpose, it is necessary to elevate the entire string ,of pipe,necessitating that the sections be disconnected at certain joints andstood in a vertical position in the derrick.

Inasmuch as the pipe sections are disconnected at these joints veryfrequently, the

regular pipe thread that has ordinarily been used becomes damaged. Forthis reason, tool joints have been devised for connecting the pipe atthese points, but they are not meeting with entire satisfaction, in thatthe threads are not so designed Ithat when they are hardened, the edgeswill not chip or break. Furthermore, such joints have been so designedthat they come into contact with the sides of the bore, andtherefore'have to be hardened on the exterior in order to avoid theabrasive action which would soon wear the joints if they were nothardened. Such hardening of the outside of the joint is undesirable forthe reason that it cannot be gripped with a pipe t ng for connecting anddisjointing the pipe ections.

It is an object of the present vention i to provide a tool joint inwhich t e threads are so designed as to have no edges or corners, which,when hardened, will be liable to chip or crack.

A further object is to provide a joint which is so constructed thatthere will be considerable clearance between it and the sides of thebore, and hence need not be hardened.

These and other objects and advantages are obtained from my invention,which is illustrated in the accompanying drawings.

In the drawings,

Fig. 1 is a vertical section showing my invention connecting twosections of pipe;

Fig. 2 is a similar section on a larger scale of the two members formingthe joint, shcwing them disconnected from each other; an

Fig. 3 is an enlarged view showing in JOINT.

27,l 1920. Serial No. 426,760.

elevation the shape of the I employ for connecting the section andthreads which two sections.

Referring to the drawings, 5 is an upper pipe section, 6 is a lower pipesection, 7 is known as the box end of the tool joint, and 8 is known asthe pin end of the tool joint.

The box-end member 7 of the tool joint is cylindrical in shape and of adiameter which is larger than the diameter of the pipe, but in practiceis less than the diameter of the bore. The upper end 9 thereof isreduced to a diameter corresponding with that of the pipe 5, and isthreadedat 10. Connecting the pipe section 5 to the joint member 7 is asleeve 0r coupling 11, said coupling being adapted to be threaded ontothe pipe section and onto the threads 10 of the reduced end 9 of thebox-end member. The coupling 11 has a diameter greater than the'diameterof the box-end member 7, and it is hardened to prevent wear by contactwiththe walls of the bore.

In the upper end of the box-end member 7 is a tapered passage 12. Theinterior of the lower end Vof the box-end member is threaded, asindicated at 13, and this threaded interior is also preferably taperedso that the lower end thereof is widest. By forming the passagestapering,as shown, I do away with all shoulders or other project-ionsliable to impede the free passage of fluid.

- The body 14 of the pin-end member 8 is also cylindrical in shape andits diameter is the same as that of the box-end member 7. The lower end15 thereof is reduced.l and threaded the same as the end 9 of the boxendmember. A coupling 16, corresponding in all respects to coupling11,-serves to connect the lower pipe section 6 with the joint member 8.The upper end 17 of the pinend member is threaded at 18 to cooperatewith the interior threads 13 of the box-end member of the joint, and hasa taper corresponding thereto. A passage 19 tapered in a directionopposite to passage 12 extends through member 8.

The s hape of the threads 13 and 18 is shown on a! large scale in 'Fig3. They are of the well known acme type, employed on cylindricalsurfaces, lar to the longitudinal axis of the threaded member, but thetops 'or crests of the threads, instead of being squared as heretofore,are rounded, as are also the bottoms of which are perpendicuf traA 'through.

the grooves between the threads. The threads are hardened, as by anywell known method of heat treatment. The shape thereof eliminates allsharp edges and corners which would be liable to chip or break, as isthe case with the usual threads when they have been hardened.

In use, the pin-end member 8 of the joint is secured to the top ot thelower pipesection (S by the hardened coupling 16. The box-end member 7is secured to the upper pipe section 5 by the hardened coupling 11.Because the connection between the pipes and the joint members is arelatively permanent one, and need not be disconnected every time thestring ot' pipe is elevated, there is no objection to hardening theoutsides ot' the sleeves 11y and 16 to prevent the wearing thereof bycontact with the sides of the bore. After the joint members 7 and 8 havebeen connected to their respective pipe sections 5 and 6, the threadedportion 18 on one end of member 8 is screwed into the threaded opening13 on the 'adjacent end of member 7.

When the pipe is elevated, the sections can be separated at thesejoints, and the threads will not readily become injured. The taperedpassageways 12 and 19 avoid shoulders on the interior of the joint whichwould check or retard the flow of water there- By reason ot thecooperating joint members 7 and 8 having adiameter less than that ol thebore and of the sleeves 11 and 16, it is unnecessary thatthey should behardened, and therefore they may be readily gripped by pipe tongs.

Vhat I claim is:

1. In' combination with two sections of pipe` a hollow jointffordetachably connecting them, said joint comprising two cylindricalmembers having cooperating threaded surfaces on their adjacent ends, andhaving their other ends threaded on the exterior thereof, andvinteriorly threaded 'hardened couplings connecting the pipe sections tothe threaded exterior ends of the joint members, said coupling being ofgreater diameter than the diameter of the pipes or the cylindricalmembers, whereby the cylindrical members are protected from wearing.

2. In combination with two sections of pipe ot' a drill shaft, of ahollow joint therefor comprising two cylindrical joint members havingcooperative threaded surfaces on their adjacent ends and having theirother ends oi' a diameter to correspond to the diameter ot the pipe,which ends are threaded on the exterior thcreot',and interiorly threadedcouplings connecting the pipe sections with the threaded exterior ends'of said joint members, said couplings having a diameter greater than thediameter ot' said joint members, and being case-hardened, whereby theyprotect the joint members from wear, said joint members having untreatedexterior surfaces whereby a wrench may readily cooperate therewith.

3. The combination with two pipe sections, ot' a hollow joint fordetachably connecting the pipe sections including two members havingcooperating hardened 'threaded portions on their adjacent ends,

and having their other ends threaded, unhardened tong engaging surfaceson said members disposed between the said threaded portions, andhardened couplings connecting the pipe sect-ions to the joint, saidcouplings being ot greater diameter than the pipe sections and the jointmembers for protccting thesaid unhardened surfaces.

In testimony whereof I aiiix my signature.

EDGAR. n. GREVE.

